Gallium nitride-based III-V nitrides, which receive attention as excellent blue light-emitting devices, are actually used for the production of light-emitting diodes, and expected to be used as optical pickup blue-violet semiconductor laser devices as well. In a method for growing a GaN single crystal described in “Jpn. J. Appl. Phys.” vol. 42 (2003), pp. L879-L881, a boron nitride crucible is placed in a pressure-resistant vessel, metallic Ga of a group III material and Na as flux are put in the boron nitride crucible, and high-pressure nitrogen gas is supplied to the pressure-resistant vessel. Then nitrogen of a group V material is dissolved in the Ga—Na mixed melt through the application of heat and pressure to grow a GaN single crystal on a seed crystal substrate in the crucible. At that time, the boron nitride crucible is oscillated by attaching a rotating shaft to an electric furnace that accommodates the boron nitride crucible, connecting the rotating shaft to a motor shaft, and then starting the motor.
Moreover, according to Japanese Patent Publication (Laid-Open) Nos. 2001-64098A and 2005-298269A, in growing a GaN single crystal by the flux method, one crucible is placed in a pressure vessel, one seed crystal is put in the crucible, and then the GaN single crystal is grown on the seed crystal.
Furthermore, Japanese Patent Application Publication (Laid-Open) No. 2004-224600A describes a case in which one crucible is placed in a pressure vessel and plural seed crystals are put in the crucible to grow plural crystals.